From 139f9d9e354eaeb6e9f1ebf6bc5abe2e903a55e2 Mon Sep 17 00:00:00 2001
From: "Juan J. Martinez" <jjm@usebox.net>
Date: Wed, 14 Sep 2022 20:15:49 +0100
Subject: Playing with some ideas

---
 src/Micro/Asm/Sdcc.hs | 44 ++++++++++++++++++++++++++------------------
 1 file changed, 26 insertions(+), 18 deletions(-)

(limited to 'src/Micro/Asm')

diff --git a/src/Micro/Asm/Sdcc.hs b/src/Micro/Asm/Sdcc.hs
index a645129..b582819 100644
--- a/src/Micro/Asm/Sdcc.hs
+++ b/src/Micro/Asm/Sdcc.hs
@@ -38,9 +38,6 @@ area name = "\n\t.area " ++ name
 globl :: String -> String
 globl id = "\t.globl " ++ id
 
-code :: [String]
-code = [area "_CODE"]
-
 data Output = Output
   { oPre :: [String],
     oInit :: [String],
@@ -52,23 +49,34 @@ emit :: A.Expr -> Output
 emit x =
   case x of
     (A.Module name _) -> o {oPre = [module' name, optsdcc, ""]}
-    (A.Func ident params ret body priv anon pos) -> do
-      let out = map emit body
-      let code = concat (map oCode out)
-      o
-        { oPre = if priv then [] else [globl $ toIdent ident],
-          oCode = [toLabel ident priv] ++ code ++ (if last code /= "\tret" then ["\tret"] else [])
-        }
     (A.Var id typ val priv False _) ->
       o
         { oPre = if priv then [] else [globl $ toIdent id],
           oData = [toLabel id priv, "\t" ++ toData typ],
-          oInit = ["__xinit" ++ toLabel id True, "\t" ++ toInit typ val]
+          oInit = ["__init" ++ toLabel id True, "\t" ++ toInit typ val]
         }
-    (A.Call (A.Variable id _) _ _) -> o {oCode = ["\tcall " ++ toIdent id]}
-    (A.Return (Just value) _) -> o {oCode = ["\tld hl, ???", "\tret"]}
-    (A.Return Nothing _) -> o {oCode = ["\tret"]}
-    _ -> o
+    (A.Num v _) -> o {oCode = ["\tld a, #" ++ show v]}
+    (A.Variable id _) -> o {oCode = ["\tld a, (" ++ toIdent id ++ ")"]}
+    -- cases where constant folding didn't happen
+    (A.BinOp A.Plus _ (A.Num a _) (A.Num b _)) -> o {oCode = [show a ++ "+" ++ show b]}
+    (A.BinOp A.Minus _ (A.Num a _) (A.Num b _)) -> o {oCode = [show a ++ "-" ++ show b]}
+    (A.BinOp A.Mul _ (A.Num a _) (A.Num b _)) -> o {oCode = [show a ++ "*" ++ show b]}
+    (A.BinOp A.Div _ (A.Num a _) (A.Num b _)) -> o {oCode = [show a ++ "/" ++ show b]}
+    (A.BinOp A.Plus _ a (A.Num 1 _)) ->
+      o {oCode = oCode (emit a) ++ ["\tinc a"]}
+    (A.BinOp A.Plus _ a@(A.Variable _ _) (A.Num v _)) ->
+      o {oCode = oCode (emit a) ++ ["\tadd #" ++ show v]}
+    (A.BinOp A.Plus _ a b) ->
+      o {oCode = oCode (emit a) ++ ["\tld c, a"] ++ oCode (emit b) ++ ["\tadd c"]}
+    (A.BinOp A.Minus _ a (A.Num 1 _)) ->
+      o {oCode = oCode (emit a) ++ ["\tdec a"]}
+    (A.BinOp A.Minus _ a@(A.Variable _ _) (A.Num v _)) ->
+      o {oCode = oCode (emit a) ++ ["\tsub #" ++ show v]}
+    (A.BinOp A.Minus _ a b) ->
+      o {oCode = oCode (emit a) ++ ["\tld c, a"] ++ oCode (emit b) ++ ["\tsub c"]}
+    (A.BinOp A.Assign _ (A.Variable id _) b) ->
+      o {oCode = oCode (emit b) ++ ["\tld (" ++ toIdent id ++ "), a"]}
+    _ -> o {oCode = [";; unimplemented " ++ show x]}
   where
     o = Output [] [] [] []
 
@@ -76,7 +84,7 @@ generate :: String -> [A.Expr] -> String
 generate version ast = do
   out <- pure $ map emit ast
   pre <- pure $ concat $ map oPre out
-  dat <- pure $ ["\n\t.area _DATA", "\t.area _INITIALIZED"] ++ concat (map oData out)
-  code <- pure $ ["\n\t.area _CODE"] ++ concat (map oCode out)
-  init <- pure $ ["\n\t.area _INITIALIZER"] ++ concat (map oInit out) ++ ["\n\t.area _GSINIT", "\t.area _GSFINAL"]
+  dat <- pure $ [area "_DATA", area "_INITIALIZED"] ++ concat (map oData out)
+  code <- pure $ [area "_CODE"] ++ concat (map oCode out) ++ ["hlt0:", "\tjr hlt0"]
+  init <- pure $ [area "_INITIALIZER"] ++ concat (map oInit out) ++ [area "_GSINIT", area "_GSFINAL"]
   unlines $ header version ++ pre ++ dat ++ code ++ init
-- 
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